Imatinib Therapy Research Articles

Peak study: A phase 3, randomized, open-label multi-center clinical study of bezuclastinib (CGT9486) and sunitinib combination versus sunitinib in patients with gastrointestinal stromal tumors (GIST).

TPS11588 Background: Imatinib is the worldwide standard for first-line therapy of advanced KIT-mutant GIST. However, secondary resistance mutations in the KIT ATP-binding domain (exons 13, 14), activation loop (exons 17, 18), or both develop and result in loss of imatinib-sensitivity. Bezuclastinib has a highly selective inhibition profile, leading to minimal off-target toxicities and allowing for combination with sunitinib. While no single tyrosine kinase inhibitor (TKI) inhibits all KIT mutations, the combination of bezuclastinib + sunitinib targets commonly occurring primary (exons 9, 11) and secondary (exons 13, 14, 17, and 18) KIT mutations and may provide more durable responses. The early signs of clinical activity, tolerability, and safety observed with the combination thus far in Peak Part 1 (Somaiah et al. [presentation] CTOS 2023. Paper 62) are consistent with the completed Phase 1/2 study (PLX121-01). Methods: Peak (NCT05208047) is a global, randomized, open-label, multi-part Phase 3 study evaluating the efficacy and safety of bezuclastinib + sunitinib versus sunitinib as second-line treatment in adult pts who were intolerant to imatinib or whose tumors had imatinib-resistance. Current Peak study sites are located in North America (3 countries), South America (3 countries), Europe (12 countries), and Asia-Pacific (4 countries). The lead-in portion to test a new formulation of bezuclastinib, (Part 1) completed enrollment in April 2023. Based upon PK and safety, a dose of bezuclastinib 600 mg QD + sunitinib 37.5 mg QD was determined for Part 2 of the Peak study. Part 2 will enroll ~388 pts to be randomized (1:1) to bezuclastinib 600 mg QD + sunitinib 37.5 mg QD or sunitinib 37.5 mg QD alone. Key inclusion: >1 measurable lesion per modified Response Evaluation Criteria in Solid Tumors (mRECIST) v1.1, Eastern Cooperative Oncology Group Performance Status 0-2, adequate organ function, and prior imatinib therapy (no other prior therapy). Key exclusion: known PDGFR mutations or succinate dehydrogenase deficiency, clinically significant cardiac disease, and use of strong CYP3A4 inhibitors or inducers. The primary endpoint is progression-free survival (PFS) confirmed by blinded independent central review per mRECIST v1.1. Additional efficacy (including overall survival and objective response rate) and safety endpoints will be evaluated and circulating tumor DNA (ctDNA) will be collected and assessed. Clinical trial information: NCT05208047 .

A systematic review and meta-analysis of neoadjuvant imatinib use in locally advanced and metastatic gastrointestinal stromal tumors.

Several doubts remain regarding the optimal use of neoadjuvant imatinib in gastrointestinal stromal tumors (GISTs), such as ideal treatment duration, patient selection, and long-term survival outcomes. This manuscript provides a comprehensive review on neoadjuvant imatinib treatment outcomes and facilitate evidence-based decision-making for the use of imatinib therapy in GISTs. Four databases (PubMed, EMBASE, Scopus, and Cochrane Library) were searched from inception to September 9, 2023. Meta-analyses of proportions were performed for the outcomes of R0 resection, disease responses, and 1-year, 3-year, and 5-year overall survival (OS) as well as 1-year, 3-year, and 5-year disease free survival (DFS). Sensitivity analyses in the form of leave-one-out analyses, meta-regression, and subgroup analyses were performed for outcomes with substantial statistical heterogeneity. The search yielded 1254 articles, and 36 studies were included in our analysis. Meta-analysis of proportions revealed that 1-year, 3-year, and 5-year OS was 100%, 94%, and 88%, while 1-year, 3-year and 5-year DFS was 99%, 89%, and 79%, respectively. An R0 resection rate of 89% and a disease response rate of 67% was achieved after a mean duration of treatment of 8.41±0.367months. KIT exon 9 mutation was significantly associated with poorer 5-year DFS. This study quantified key outcomes for neoadjuvant imatinib in locally advanced and metastatic or recurrent GIST. Patients with gastric and rectal tumous stand to benefit from neoadjuvant imatinib with an optimal treatment duration of 8months. Furthermore, the potential utility of mutational analysis in guiding treatment with neoadjuvant imatinib was demonstrated.

Short-term and long-term outcomes after robotic radical surgery for rectal gastrointestinal stromal tumor

BackgroundThe optimal approach for ensuring both complete resection and preservation of anal function in rectal gastrointestinal stromal tumor (GIST) remains unknown. The aim of this study was to clarify short-term and long-term outcomes after robotic radical surgery for rectal GIST.MethodsA total of 13 patients who underwent robotic radical surgery for rectal GIST between December 2011 and April 2022 were included. All robotic procedures were performed using a systematic approach. A supplemental video of robotic radical surgery for rectal GIST is attached. The short-term outcome was the incidence of postoperative complications during the first 30 days after surgery. Surgical outcomes were retrieved from a prospective database. Long-term outcomes, including overall survival and recurrence-free survival, were determined in all patients.ResultsMedian distance from the tumor to the anal verge was 4.0 cm. Surgical margins were negative in all patients. Two patients underwent neoadjuvant imatinib therapy. All patients underwent sphincter-preserving surgery. None underwent conversion to open or laparoscopic surgery. The incidence of postoperative Clavien-Dindo grade II and grade ≥ III complications was 7.7% and 0%, respectively. The median postoperative hospital stay was 7 days. Twelve patients (92.3%) underwent stoma closure within 5 months of the initial surgery. Median follow-up time was 76 months. The 5-year overall survival and recurrence-free survival rates were both 100%. None of the patients had recurrence.ConclusionShort-term and long-term outcomes after radical robotic surgery for rectal GIST were favorable. Robotic surgery might be a useful surgical approach for rectal GIST.

A pure endoscopic full-thickness resection of a large non-metastatic GI stromal tumor >5 cm of the stomach after neoadjuvant imatinib therapy

A pure endoscopic full-thickness resection of a large non-metastatic GI stromal tumor >5 cm of the stomach after neoadjuvant imatinib therapy

Myxoid Inflammatory Myofibroblastic Sarcoma: Clinicopathologic Analysis of 25 Cases of a Distinctive Sarcoma With Deceptively Bland Morphology and Aggressive Clinical Behavior.

The number of recognized sarcoma types harboring targetable molecular alterations continues to increase. Here we present 25 examples of a distinctive myofibroblastic tumor, provisionally termed "myxoid inflammatory myofibroblastic sarcoma," which might be related to inflammatory myofibroblastic tumor, and which occurred in 13 males (52%) and 12 females at a median age of 37 years (range: 7 to 79 years). Primary tumor sites were peritoneum (18 patients; 72%), paratesticular (2; 8%), chest wall (1), upper extremity (1), esophagus (1), retroperitoneum (1), and uterus (1). Nine peritoneal tumors (50%) were multifocal at presentation; all other tumors were unifocal. Tumors showed bland-to-mildly-atypical neoplastic myofibroblasts in a myxoid stroma, with prominent inflammatory infiltrates in 22 cases (88%). Most tumors showed delicate branching stromal vessels like those of myxoid liposarcoma, and most showed infiltrative growth through non-neoplastic tissue. Immunohistochemistry demonstrated expression of SMA (19/25 tumors; 76%), desmin (13/22; 59%), and CD30 (5/11; 45%), while ALK was expressed in 1 tumor (of 25; 4%) that was negative for ALK rearrangement. Sequencing of 11 tumors showed seven to harbor tyrosine kinase fusions (4 PDGFRB , 2 PML :: JAK1 , 1 SEC31A :: PDGFRA ). Two instead harbored hot spot KRAS mutations (G12V and Q61H), and 2 were negative for known driving alterations. Clinical follow-up was available for 18 patients (72%; median: 2.7 years; range: 4 mo-12.3 years). Nine patients (50%) were alive with no evidence of disease, 5 (28%) died of disease, and 4 (22%) were alive with disease. Seven patients (39%) experienced peritoneal relapse or distant metastasis. Two patients showed disease progression on conventional, nontargeted chemotherapy. The patient whose tumor harbored SEC31A :: PDGFRA was treated after multiple relapses with imatinib and sunitinib therapy, with progression-free periods of 5 and 2 years, respectively. Despite its bland appearance, myxoid inflammatory myofibroblastic sarcoma harbors a significant risk for disseminated disease, particularly when it occurs in the peritoneum. Targeted therapy could be considered for patients with disseminated disease.

Treatment of chronic-phase chronic myeloid leukemia in patients randomized to dasatinib or imatinib after suboptimal responses to 3 months of imatinib therapy: final 5-year results from DASCERN.

Early molecular response at 3 months is predictive of improved overall survival and progression-free survival in patients with chronic myeloid leukemia in the chronic phase. Although about one-third of patients treated with first-line imatinib do not achieve an early molecular response, long-term overall survival and progression-free survival are still observed in most patients. DASCERN (NCT01593254) is a prospective, phase IIb, randomized trial evaluating a switch to dasatinib in patients who have not achieved an early molecular response after 3 months of treatment with first-line imatinib. Early analysis demonstrated an improved major molecular response (MMR) rate at 12 months with dasatinib versus imatinib (29% vs. 13%, P=0.005). Here, we report results from the final 5-year follow-up. In total, 174 patients were randomized to dasatinib and 86 to remain on imatinib. Forty-six (53%) patients who remained on imatinib but subsequently experienced failure were allowed to cross over to dasatinib per protocol. At a minimum follow-up of 60 months, the cumulative MMR rate was significantly higher in patients randomized to dasatinib than those randomized to imatinib (77% vs. 44%, P<0.001). The median time to MMR was 13.9 months with dasatinib versus 19.7 months with imatinib. The safety profile was consistent with previous reports. These results demonstrate that switching to dasatinib after a suboptimal response to imatinib at 3 months leads to faster MMR, provides earlier deep molecular responses, and improves some outcomes in patients with chronic myeloid leukemia in the chronic phase.

Efficacy and safety of flumatinib in the treatment of newly diagnosed chronic myeloid leukemia in the chronic phase: A real-world single-center retrospective study, with a focus on premature drug discontinuation

PurposeTo assess the real-world efficacy and safety of flumatinib as first-line and post-line treatments for chronic myeloid leukemia in the chronic phase (CML-CP). ResultsAmong 141 patients receiving flumatinib as first-line and post-line treatment, the 12-month major molecular response (MMR) rates were 69.4% and 67.6%, respectively. The median time to response was 6 and 10.5 months, respectively. In post-line treatment, the early molecular response (EMR) of flumatinib as second-line is significantly superior to that of third-line treatment (3-month EMR rate: 79.2% vs. 39.3%, P<0.001; 3-month MMR rate: 45.8% vs. 21.4%, P=0.033). Contrastively, patients who switched to flumatinib due to intolerance had significantly higher MMR rates at 3, 6, and 12 months compared to patients who switched due to inadequate response (60.6% vs. 24.2%, P=0.003; 66.7% vs. 36.0%, P=0.027; 84.2% vs. 50.0%, P=0.038). Premature drug discontinuation was observed in 28.4% of the patients. Grades 3–4 hematologic adverse events (AEs) were identified as independent risk factors for premature drug discontinuation. Patients who discontinued treatment and those who previously received only imatinib therapy had a poorer molecular response and failure-free survival. ConclusionsFlumatinib demonstrates favorable efficacy and safety. Treatment discontinuation can result in a poorer molecular response and long-term prognosis.

Лечение агрессивного системного мастоцитоза и тучноклеточного лейкоза. Обзор литературы и серия клинических наблюдений

Aim. To provide case reports on the course and treatment of aggressive systemic mastocytosis (ASM) and mast cell leukemia (MCL).&#x0D; Materials &amp; Methods. This paper reports the histories of adult patients with ASM (n = 4) and MCL (n = 2) treated with cytoreduction predominantly at the City Clinical Hospital No. 31 (Saint Petersburg). The patients were 36–61 years of age (median 50 years); there were 4 women and 2 men.&#x0D; Results. All patients showed stable response to cladribine (n = 3), imatinib (n = 2), and combined lenalidomide, elotuzumab, and dexamethasone treatment with subsequent allogeneic hematopoietic stem cell transplantation (n = 1). With a median follow-up of 124 months (range 55–186 months), 1 out of 2 MCL patients died due to the concomitant hypereosinophilic syndrome progression and secondary infectious complication.&#x0D; Conclusion. Cladribine therapy in 2 ASM patients and imatinib therapy in 2 MCL patients yielded stable long-term response with good quality of life being maintained. More comparative studies are required for efficacy assessment and optimum sequencing of chemotherapeutic drugs.

Identification of Novel Stemness-based Subtypes and Construction of a Prognostic Risk Model for Patients with Lung Squamous Cell Carcinoma.

Although cancer stem cells (CSCs) contribute to tumorigenesis, progression, and drug resistance, stemness-based classification and prognostic signatures of lung squamous cell carcinoma (LUSC) remain unclarified. This study attempted to identify stemness-based subtypes and develop a prognostic risk model for LUSC. Based on RNA-seq data from The Cancer Genome Atlas (TCGA), Gene-Expression Omnibus (GEO) and Progenitor Cell Biology Consortium (PCBC), mRNA expression-based stemness index (mRNAsi) was calculated by one-class logistic regression (OCLR) algorithm. A weighted gene coexpression network (WGCNA) was employed to identify stemness subtypes. Differences in mutation, clinical characteristics, immune cell infiltration, and antitumor therapy responses were determined. We constructed a prognostic risk model, followed by validations in GEO cohort, pan-cancer and immunotherapy datasets. LUSC patients with subtype C2 had a better prognosis, manifested by higher mRNAsi, higher tumor protein 53 (TP53) and Titin (TTN) mutation frequencies, lower immune scores and decreased immune checkpoints. Patients with subtype C2 were more sensitive to Imatinib, Pyrimethamine, and Paclitaxel therapy, whereas those with subtype C1 were more sensitive to Sunitinib, Saracatinib, and Dasatinib. Moreover, we constructed stemness-based signatures using seven genes (BMI1, CCDC51, CTNS, EIF1AX, FAM43A, THBD, and TRIM68) and found high-risk patients had a poorer prognosis in the TCGA cohort. Similar results were found in the GEO cohort. We verified the good performance of risk scores in prognosis prediction and therapy responses. The stemness-based subtypes shed novel insights into the potential roles of LUSC-stemness in tumor heterogeneity, and our prognostic signatures offer a promising tool for prognosis prediction and guide therapeutic decisions in LUSC.

Impact of MDR-1 Gene Polymorphism (rs1128503) on Response to Imatinib or Nilotinib in Iraqi Patients with Chronic Myeloid Leukemia: An Observational Study

Background: There is a significant molecular response to imatinib given at standard doses in individuals with chronic myeloid leukemia (CML) whose ABCB1 polymorphisms are present. Objective: To investigate the impact of the polymorphism in the ABCB1 gene rs1128503 on the effectiveness of nilotinib or imatinib therapy. Methods: From May 2022 until the end of January 2023, the current study was carried out in a single research institution, the National Center of Hematology, Baghdad Teaching Hospital at Medical City, Iraq. 76 people with chronic phase myeloid leukemia (CML-CP), who had previously received a diagnosis using the European Leukemia Net (ELN) criteria, enrolled in the trial. The PCR product was delivered to Macrogen Corporation, Korea, for Sanger sequencing on an automated DNA sequencer, the ABI3730XL. After receiving the results by email, Geneious Prime software was used for analysis. Results: Patients receiving imatinib or nilotinib did not differ significantly in terms of age or gender. In contrast, BCR-ABL1 transcript levels were considerably greater at sampling in patients receiving nilotinib. Different types of the MDR-1 gene rs1128503 genotype were not found in groups that were treated with either imatinib or nilotinib. Conclusions: BCR-ABL1 transcript levels are lower in patients still receiving imatinib than in those receiving nilotinib.

Surgical outcomes of locally advanced gastrointestinal stromal tumors after multivisceral resection: A retrospective study of 64 patients at a single institution.

To analyze the outcome in patients who have undergone multivisceral resection (MVR) for locally advanced gastrointestinal stromal tumors (GISTs), and identify the risk factors for tumor recurrence and postoperative morbidity. Sixty-four patients who operated for locally advanced GISTs with MVR in PPeking University Cancer Hospital Sarcoma Center (PUCHSC) between 2013 and 2021 were identified. Clinicopathologic characteristics, surgical outcomes, recurrence, and 5-year recurrence-free and overall survival were evaluated. The mean age of the patients was 60 years. Mean tumor size was 11.1 cm. Complete resection was achieved in all patients. The estimated 5-year recurrence-free and overall survival were 86.6% and 90.0%, respectively. Independent factor of recurrence following surgery was mitotic count on multivariate analysis. Overall postoperative morbidity was 53.1% (n = 34). Severe morbidity was 21.9% (n = 14). The most common severe complication was clinically relevant pancreatic fistula (n = 12, 18.8%), followed by anastomotic leakage (n = 4, 6.3%) and Intraabdominal abscess (n = 4, 6.3%). Multivariate analysis showed that preoperative imatinib therapy could reduce overall morbidity. Long operation time, combined colectomy and pancreatectomy were independent risk factors for postoperative severe morbidity. Compared to partial pancreatectomy, pancreaticoduodenectomy (PD) was significantly increased the incidence of severe morbidity. In conclusion, compared to systemic therapy alone, the outcome of locally advanced GISTs after MVR was more favorable. Despite the high overall morbidity, the postoperative severe morbidity and mortality of MVR were acceptable. Preoperative imatinib therapy should be recommended whenever possible. Combined pancreatectomy and colectomy are associated with significant postoperative severe morbidities. PD should be thoroughly discussed and be subject to MDT approach before surgery.

Comparison of the Efficacy Among Nilotinib, Dasatinib, Flumatinib and Imatinib in Newly Diagnosed Chronic-Phase Chronic Myeloid Leukemia Patients: A Real-World Multi-Center Retrospective Study

BackgroundThere are limited data comprehensively comparing therapy responses and outcomes among nilotinib, dasatinib, flumatinib and imatinib for newly diagnosed chronic-phase chronic myeloid leukemia in a real-world setting. Patients and MethodsData from patients with chronic-phase CML receiving initial a second-generation tyrosine-kinase inhibitor (2G-TKI, nilotinib, dasatinib or flumatinib) or imatinib therapy from 77 Chinese centers were retrospectively interrogated. Propensity-score matching (PSM) analyses were performed to to compare therapy responses and outcomes among these 4 TKIs. Results2,496 patients receiving initial nilotinib (n = 512), dasatinib (n = 134), flumatinib (n = 411) or imatinib (n = 1,439) therapy were retrospectively interrogated in this study. PSM analyses indicated that patients receiving initial nilotinib, dasatinib or flumatinib therapy had comparable cytogenetic and molecular responses (p = .28-.91) and survival outcomes including failure-free survival (FFS, p = .28-.43), progression-free survival (PFS, p = .19-.93) and overall survival (OS) (p values = .76-.78) but had significantly higher cumulative incidences of cytogenetic and molecular responses (all p values < .001) and higher probabilities of FFS (p < .001-.01) than those receiving imatinib therapy, despite comparable PFS (p = .18-.89) and OS (p = .23-.30). ConclusionNilotinib, dasatinib and flumatinib had comparable efficacy, and significantly higher therapy responses and higher FFS rates than imatinib in newly diagnosed CML patients. However, there were no significant differences in PFS and OS among these 4 TKIs. These real-world data may provide additional evidence for routine clinical assessments to identify more appropriate therapies.

A rare presentation of jejunal GIST: A case report

Gastrointestinal stromal tumors (GISTs) are rare tumors that constitute 1% of all GI tract tumors. Jejunal GISTs are the rarest subtype. We present a middle-aged gentleman, who presented with pain in the right lower abdomen. On abdominal examination, a lump was palpable in the right iliac fossa (RIF). Contrast-enhanced computed tomography of the abdomen revealed an extraluminal soft-tissue mass in the ileum. Computed Tomography-guided core needle biopsy from the lump was consistent with GIST, which was confirmed on immunohistochemistry. Mutation analysis revealed exon 11 mutations. Due to the proximity of GIST to the rectum and urinary bladder, the patient was started on imatinib therapy. After 3 months of treatment, imatinib therapy had to be stopped due to skin reactions. Restaging was done with a positron-emission tomography scan, which demonstrated a soft-tissue mass likely arising from the ileocecal region in the RIF abutting the ascending colon without any significant decrease in size. On exploration, a well-circumscribed mobile extraluminal lobulated mass was seen arising from the antimesenteric border of the jejunum. Histopathologic examination showed GIST, which was confirmed on immunohistochemistry. We report this case to emphasize keeping small bowel GIST as an unusual differential diagnosis of a RIF lump. Furthermore, not all patients can tolerate imatinib treatment, hence exon mutation study is important, and surgery should be considered if it is deemed resectable.

Gastro Intestinal Stromal Tumor -Supra Pubic Region

Gastrointestinal stromal tumours (GISTs) are rare mesenchymal neoplasms of the gastrointestinal tract and mesentery. They are usually found in the stomach or small intestine but can occur anywhere along the GIT and rarely have extra GI involvement. They are associated with high rates of malignant transformation. Most GISTs present asymptomatically but also present with bleeding, abdominal pain, and rarely gastric outlet obstruction. There have been many risk stratification classifications systems which are calculated based on tumour size, mitotic rate, location, and perforation. They are best identified by computed tomography (CT) scan and most stain positive for CD117 (C-Kit), CD34, and/or DOG-1. The approaches to treating GISTs are to resect primary low-risk tumours, high-risk tumours and further treated with imatinib therapy and unresectable tumours treated with neoadjuvant imatinib 400 mg daily followed by surgical resection and regular follow up by abdominal CT scan.

Characteristics and predictors of outcomes with neoadjuvant imatinib in gastrointestinal stromal tumors: Real-world data from a large patient registry.

737 Background: The standard of care for patients with moderate or high-risk resectable gastrointestinal stromal tumors (GIST) is surgical resection followed by adjuvant therapy with imatinib. The impact of neoadjuvant imatinib on long-term outcomes is largely unknown. Methods: We interrogated the LifeRaft registry, a large international open cohort of patients with GIST. We included patients who did not have metastatic disease at diagnosis, underwent surgical resection and received neoadjuvant imatinib and had no recorded mutations of Kit exon 13 or PDGFRA exon 18 D842V. Baseline patient characteristics were described and survival probabilities were estimated and plotted using the Kaplan-Meier method. Cox regression was used to estimate the effect of demographic and clinical characteristics on recurrence-free survival (RFS) and overall survival (OS). For RFS, time was calculated from the date of surgery to disease recurrence/death, whichever came first. For OS, time was calculated from the date of surgery to death. Estimated effects of predictors were reported as hazard ratios (HR) along with 95% confidence intervals (CI). All statistical testing was two-sided and assessed for significance at the 5% level using SAS v9.4 (SAS Institute, Cary, NC). Results: Out 2,472 patients with GIST, 137 patients met the inclusion criteria and received neoadjuvant imatinib for a median of 6.8 months. Majority of the patients were aged 40 years or above (129/137, 94.2%) and were males (73/137, 53.3%). The majority of the patients had gastric GIST (72/137, 54.1%), followed by small intestine GIST (34/137, 25.6%) and other (27/137, 20.3%). Most patients had a tumor size of &gt;10 cm (66/137, 52.4%) at the time of diagnosis followed by &gt;5 cm - &lt;=10 cm (42/137, 33.3%) and &gt;2 cm - &lt;=5 cm (18/137, 14.3%). The median RFS for the cohort was 6.1 years. On multivariable analysis, tumor size (HR 1.08, 95% CI 1.05-1.12, p&lt;0.01) and the overall duration of treatment (neoadjuvant and adjuvant) with imatinib therapy (HR 0.98, 95% CI 0.97-0.99, p&lt;0.01) were significantly associated with RFS. A 1-cm increase in tumor size and 1-month increase in total time on imatinib was associated with an 8% increase and 2% decrease in risk of recurrence. The median OS was 14.2 years. Female gender (HR 0.23 95% CI 0.08-0.65, p&lt;0.01) and total length of time on imatinib (HR 0.97 95% CI 0.96-0.99, p&lt;0.01) were found to be significantly associated with OS. Female patients were associated with a 77% decreased risk of death and a 1-month increase in the total time on imatinib was associated with a 3% decrease in the risk of death. Conclusions: We show that most patients receiving neoadjuvant imatinib have gastric GIST with tumor size &gt;10 cm. Smaller tumor size and female gender predicted longer RFS and OS respectively. Longer total duration of imatinib therapy was associated with increased RFS and OS.

Peak study: A phase 3, randomized, open-label multicenter clinical study of bezuclastinib (CGT9486) and sunitinib in combination versus sunitinib in patients with gastrointestinal stromal tumors (GIST).

TPS766 Background: Imatinib is the worldwide standard for first-line therapy of advanced KIT-mutant GIST. However, secondary resistance mutations in the KIT ATP-binding domain (exons 13, 14), activation loop (exons 17, 18), or both develop and result in loss of imatinib-sensitivity. While no single tyrosine kinase inhibitor (TKI) inhibits all KIT mutations, the combination of bezuclastinib + sunitinib targets commonly occurring primary (exons 9, 11) and secondary (exons 13, 14, 17, and 18) KIT mutations. In a Phase 1/2 clinical study, pts with relapsed and/or refractory GIST and a median of 3 prior lines of therapy treated with bezuclastinib + sunitinib (n=15) experienced clinical benefit and an acceptable safety profile, warranting further evaluation in a randomized trial. Methods: Peak (NCT05208047) is a global, randomized, open-label, multi-part Phase 3 study evaluating the efficacy and safety of bezuclastinib + sunitinib versus sunitinib as second-line treatment in adult pts who were intolerant to imatinib or whose tumors had imatinib-resistance. The lead-in portion, to test a new formulation of bezuclastinib, (Part 1) has completed enrollment. Based upon PK and safety, a dose of bezuclastinib 600 mg QD + sunitinib 37.5 mg QD has been determined for Part 2 of the Peak study. Part 2 will enroll ~388 pts to be randomized (1:1) to bezuclastinib 600 mg QD + sunitinib 37.5 mg QD or sunitinib 37.5 mg QD alone. Key inclusion: &gt;1 measurable lesion per modified Response Evaluation Criteria in Solid Tumors (mRECIST) v1.1, Eastern Cooperative Oncology Group Performance Status 0-2, adequate organ function, and prior imatinib therapy (no other prior therapy). Key exclusion: PDGFR mutations or succinate dehydrogenase deficiency, clinically significant cardiac disease, and use of strong CYP3A4 inhibitors or inducers. The primary endpoint is progression-free survival (PFS) confirmed by blinded independent central review per mRECIST v1.1. Additional efficacy (including overall survival and objective response rate) and safety endpoints will be evaluated. Clinical trial information: NCT05208047 .

Lichenoid and psoriasiform drug induced rush during imatinib therapy: a clinical case

Tyrosine kinase inhibitor imatinib is a standard agent for treatment of gastrointestinal stromal tumors (GIST). Treatment courses are quite long and are usually well tolerated. However, skin rash can occur on treatment, with a prevalence of 7 to 88.9%. We describe a clinical case of a patient with GIST, who has been on treatment with imatinib at daily dose of 400 mg for one year. Several weeks from the treatment initiation, she had facial edema, and 4 months thereafter psoriasiform rash appeared which was initially considered to be psoriatic. After 8 months, the patient had lichenoid rash on the inguinal skin and oral, tongue and vulvar mucosae. Clinically, the lichenoid rash was similar with lichen ruber planus. To confirm the diagnosis, we performed biopsy of psoriasiform and lichenoid foci. Histological examination verified the drug-induced rash. Topical treatment of psoriasiform rash with glucocorticosteroids resulted in regression of some plaques, although a proportion of them persisted. Inguinal and vulvar lichenoid rashes completely regressed and numbers of oral and tongue foci decreased after a 6-week daily application of the 0.1% tacrolimus cream. Treatment with imatinib 400 mg daily was not interrupted. The clinical observation illustrates the possibility of skin and mucosal lichenoid and psoriasiform rash simultaneously during treatment with imatinib and demonstrates the first successful experience in the treatment of lichenoid rashes with 0.1% tacrolimus cream.

CFL1 is Implicated in Chronic Myeloid Leukemia Response during Imatinib Therapy.

Cofilin (CFL1) is one critical member of the actin deploy family (ADF). Overexpression of CFL1 is associated with aggressive features and poor prognosis in malignancies. We evaluated the expression of CFL1 in patients with chronic myeloid leukemia in the chronic phase (CML-CP), acute myelocytic leukemia (AML) and healthy controls. The role of CFL1 in imatinib therapy was also investigated using cell line. We found that the expression of CFL1 was lower in CML patients than that in healthy controls, and was significantly upregulated after imatinib therapy (p<0.05). CML patients with lower CFL1 achieved higher Major molecular response (MMR) rate after 6 months of imatinib therapy (p<0.05). Cofilin, P-cofilin and F-actin, especially branched F-actin were all upregulated after imatinib therapy. The lower CFL1 expression before treatment may predicts a better response to imatinib. Imatinib affects F-actin remodeling in CML patients by regulating CFL1 expression and activity.

MYELOPROLIFERATIVE HYPEREOSINOPHILIC SYNDROME A RARE CAUSE OF DILATED CARDIOMYOPATHY WITH A REVIEW

Hypereosinophilic syndrome (HES) is aheterogenous group of rare haematological disorders, the majority of which are idiopathic. Cardiac manifestations of HES are rare and the myeloproliferative HES (M-HES) is very rare. Eosinophilic myocarditis and endomyocardial fibrosis are a typical course of morbidity and mortality in hypereosinophilic syndrome. We present a case of idiopathic eosinophilia who presented with dyspnea, abdominal distention and edema with peripheral eosinophilia (82%) in a complete blood count test done before presentation to us. Echocardiography showed enlarged cardiac chambers, global hypokinesia,moderate to severe tricuspid regurgitation, with reduced left ventricular ejection fraction &lt;40% suggestive of dilated cardiomyopathy (DCM). Parasitic disease, autoimmune disease and drug induced cardiomyopathy were excluded as possibilities. He was treated with steroids, imatinib, and anti failure therapy. Cardiac function improved with therapy and the eosinophilic count reduced. Monitoring chest radiography and electrocardiogram and echocardiography according to fluctuations in eosinophils may enable early detection and treatment of cardiac involvement in patients with HES.

Long-term results of therapy for chronic myeloid leukemia: a 20-year analysis of the use of tyrosine kinase inhibitors in Russia

Introduction. In Russia, within the framework of the GIPAP program, in the period from 2001 to 2007 at the National Medical Research Center for Hematology, imatinib therapy was initiated in 235 patients in the chronic phase of chronic myelogenous leukemia (CML).Aim: to analyze the long-term results of therapy in patients with CML who started imatinib therapy as part of the GIPAP program.Methods. A retrospective analysis of the results of therapy was performed in 235 patients with СР CML, who received imatinib under the GIPAP program from 2001 to 2007 at the National Medical Research Center for Hematology. The protocols for therapy and monitoring of the residual disease of patients at various time intervals were determined by the clinical recommendations relevant at that time in the conditions of real clinical practice and the possibilities of the patient’s region of residence. Overall survival and survival without discontinuation of imatinib therapy, univariate and multivariate analysis of overall survival were performed. The cumulative incidence of responses was calculated. An analysis of response factors, the probability of death from concomitant diseases and death from CML was carried out.Results. The median follow-up of living patients at the time of analysis was 17.3 years (IQR 15.5–18.5). 70 (30 %) patients died, with the median time to death from the start of therapy being 7.8 years (IQR 3.7–13.6). The overall 10-year, 15-year and 20-year survival rates were 82 %, 74 % and 62 %. The cause of death in 43 cases (61%) was the progression of CML to the phase of acceleration or blast crisis and death out of remission for an unspecifi ed cause. 27 (39%) patients died from causes not related to CML. Patient age at initiation of imatinib therapy, length of time from diagnosis to initiation of imatinib therapy, and Sokal and ELTS risk groups at disease onset were identifi ed as signifi cant for survival by univariate analysis. Multivariate analysis showed independent predictive value for overall survival for age at initiation of imatinib therapy, length of illness before imatinib treatment, and ELTS risk group at disease onset. Among patients who died from CML progression, the proportion of patients who did not achieve CCyR for the entire period of therapy before death was 83% (35/42), while among patients who died from concomitant diseases, the proportion of patients without CCyR for the entire period of therapy was 11 % (p &lt; 0.0001). The median duration of imatinib therapy was 11.4 years (0.8–21 years). 40 people died during imatinib therapy, 103 patients are alive and continue therapy with imatinib, 92 patients received at least one second-generation of Tyrosine kinase inhibitors (TKI) (TKI2), of which 62 people are alive and continue treatment with TKI. No more than two lines of TKI therapy were received by 49 (21 %) patients, and three or more lines were prescribed to 43 (18 %) patients. The median duration of therapy after switching to TKI2 was 7.8 years (0.1–15.6 years). Overall 15-year survival after switching to TKI2 was 59 %. On therapy with imatinib, during the entire observation period, complete cytogenetic response (CCyR) was achieved in 171 patients (73 %), another 18 patients (8 %) achieved CCyR for the fi rst time after switching to TKI2. Major (MMR) and deep molecular response (DMR) were achieved with imatinib in 129 (56 %) and 124 (53 %) patients, with TKI2 TKI2 therapy in 38 (16 %) and 33 (14 %) patients, respectively. Multivariate analysis showed an independent predictive value of only the time period from diagnosis to the start of imatinib treatment for achieving molecular responses to TKI therapy.Conclusion. After 20 years of monitoring patients on TKI therapy, we still cannot say that survival in CML is comparable to the survival of normal population. Long-term follow-up confi rms the fact that tumor reduction to at least the level of CCyR is the most signifi cant surrogate marker associated with a reduced risk of death from CML. Timely diagnosis of the disease, rapid initiation of targeted therapy and the fastest possible induction of cytogenetic and molecular responses is a very important mechanism for reducing the risk of resistant course and progression of CML.